1. Technical Field
The present disclosure relates to a perfusion apparatus and method. The structures disclosed are particularly suited for transmyocardial revascularization (TMR).
2. Background of the Related Art
A variety of procedures and apparatus have been developed to treat cardiovascular disease. For example, minimally invasive surgical procedures such as balloon angioplasty and atherectomy have received extensive investigation and are in wide use. In some patients, however, circumstances still require conventional open heart bypass surgery to correct or treat advanced cardiovascular disease. In some circumstances, however, patients may not be suitable candidates for bypass surgery.
An alternative or adjunct procedure to bypass surgery is transmyocardial revascularization (TMR), wherein holes are formed in the heart wall. These holes theoretically provide alternative blood flow channels for ischemic heart tissue and have been attributed to decreased pain (angina) associated with cardiovascular disease. The holes can be created using laser energy. In early laser myocardial revascularization, a CO.sub.2 laser was used to produce holes in the heart wall by transmitting laser energy from the laser to the heart wall. Typical CO.sub.2 lasers used for transmyocardial revascularization (TMR) are externally located and have an articulated support arm for aiming and directing laser energy through a series of mirrors that reflect the energy onto the heart wall. Thus, some surgical opening of the chest wall is required to access the heart muscle. The entrance wound in the heart can be closed by relatively brief external pressure while the endocardial and myocardial layers remain open to permit blood flow from the ventricle to the heart muscle.
Less traumatic approaches to laser myocardial revascularization have been disclosed. These methods include the use of optical fibers introduced either through a patient's vasculature or, alternatively, directly into the patient's chest cavity. The intravascular method involves the direction of laser energy from inside the heart to form a bore in the heart wall while the other method involves introduction of the lasing apparatus through a relatively small incision in the patient's chest to access the outer wall of the heart.
During a conventional procedure, typically dozens of channels are created from the epicardium, through the myocardium and endocardium and into the ventricle, with each channel being of sufficiently small diameter such that the end portions of the channels at the epicardium can be closed by blood clotting. The channels are preferably created by employing either a mechanical coring apparatus or an advancing lasing device. With either technique, an important objective is to produce channels that remain patent in the long term and which do not close up due to fibrosis and/or scarring. Channel closure can reduce or eliminate the benefits attributable to TMR procedures.
Therefore, there is a need for devices and methods for ensuring that TMR channels remain open to allow oxygen rich blood to reach the desired areas of the myocardium.